Sometimes there is no "claim steam key" section on the download page of games that provides steam key. The developer says there are steam keys available to claim but there is no "claim steam key" button in the download page. This happened to Fumiko! and Splinter Zone. It happened to Samorost 2 before but when I checked it today it has the "claim steam key" button and it's available to claim.

Sometimes there might some delay if a purchase needs review. If you have an issue you can contact support and they can look up your purchases. We don't do account support on the message board.